Automated circumferential Barrett's ablation by using radiofrequency energy: a welcome step in the right direction

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

Prospective randomized trial of argon plasma coagulation ablation versus endoscopic surveillance of Barrett's esophagus in patients treated with antisecretory medication

Argon plasma coagulation (APC) has been used to ablate Barrett's esophagus, however, its role in the management of non-dysplastic Barrett's esophagus is uncertain. The purpose of this study is to determine the efficacy of endoscopic argon plasma coagulation (APC) for ablation of Barrett's esophagus in a prospective randomized controlled trial in two university teaching hospitals. Fifty-seven patients using proton pump inhibitor (PPI) medication and with Barrett's esophagus were randomized to undergo either ablation using endoscopic argon plasma coagulation (APC) or ongoing surveillance. Fifty-one patients underwent endoscopy at 12 months. Endoscopic argon plasma coagulation (APC) versus surveillance endoscopy was studied. Endoscopy and histopathological appearances of Barrett's esophagus at 12 months follow-up was also studied. Initially, at least 95% ablation of the metaplastic mucosa was achieved in 25 of the 26 treated patients. At 12 months, 14 of 23 APC patients had at least 95% regression, and nine of 23 had complete regression of Barrett's esophagus. No surveillance patient had more than 95% regression. The length of Barrett's esophagus shortened significantly after APC (mean 3.0 vs. 0.5 cm). Significant regression of Barrett's esophagus follows ablation with APC, although complete regression was achieved in less than half. The role of APC ablation of non-dysplastic Barrett's esophagus remains uncertain.

Early experience with radiofrequency energy ablation therapy for Barrett's esophagus with and without dysplasia

Radiofrequency (RF) ablation using the HALO(360) system combined with proton pump inhibitor (PPI) therapy is a new treatment for Barrett's esophagus (BE). We assessed the safety and effectiveness of this combination therapy at a community-based, BE referral center. After symptom evaluation, endoscopy and histologic assessment, esophageal motility, pH monitoring on PPI, computed tomography, endoscopic ultrasonography and mucosal resection for nodules, we performed HALO(360) ablation followed by twice daily PPI and 3-monthly surveillance for up to 12 months. If metaplasia or dysplasia were present at follow-up, the patients received a second ablation. Thirteen patients (12 male) were treated, three with high-grade dysplasia, four with low-grade and six with non-dysplastic intestinal metaplasia. The mean baseline BE length was 6 cm (range 2-12); nine patients had an hiatal hernia and two had a prior fundoplication. Esophageal pH < 4.0 for < 4% of time was achieved only in 5/13 patients. A mean of 1.4 ablation sessions were performed, without serious adverse events or strictures. Complete eradication of BE was achieved in 6/13 (46%) patients. The mean endoscopic surface regression was 84% (from a mean length of 6 +/- 1 cm to 1.2 +/- 0.5 cm, P < 0.001). Complete elimination of dysplasia was achieved in 5/7 (71%) patients. Ablation efficacy was better in those patients who had maximal pH control (P < 0.05). HALO(360) ablation of BE with or without dysplasia is safe, well-tolerated and effective in the community setting. Follow-up ablation further reverses residual BE or dysplasia.